Molding resin composition including chlorinated vinyl chloride-based resin, and molded article thereof

ABSTRACT

The present invention aims to provide a chlorinated vinyl chloride-based resin composition with excellent thermal stability and a molded body thereof. The present invention relates to a resin composition for molding, including a chlorinated vinyl chloride-based resin, a thermal stabilizer, and a polyalcohol and/or a partial ester of a polyalcohol. The chlorinated vinyl chloride-based resin has a chlorine content of 65% by weight or more and less than 72% by weight. The chlorinated vinyl chloride-based resin has, based on the total number of moles of a structural unit (a) —CCl 2 —, a structural unit (b) −CHCl—, and a structural unit (c) —CH 2 —, a proportion of the structural unit (a) of 17.5 mol % or less, a proportion of the structural unit (b) of 46.0 mol % or more, and a proportion of the structural unit (c) of 37.0 mol % or less. The thermal stabilizer contains at least one of a compound represented by the formula Ca 1-x Zn x  (OH) 2  where x satisfies the inequality 0&lt;x&lt;1 and a compound represented by the formula Ca 1-y Zn y O where y satisfies the inequality 0&lt;y&lt;1.

TECHNICAL FIELD

The present invention relates to a resin composition for moldingcontaining a chlorinated vinyl chloride-based resin, and a molded bodythereof.

BACKGROUND ART

Chlorinated vinyl chloride-based resin compositions have been widelyused as a material of resin molded bodies, such as building materials.Chlorinated vinyl chloride-based resin compositions are required to havehigh thermal stability for processing at high temperatures. They needhigh thermal stability also in order to provide a molded body havingthermal stability. Chlorinated vinyl chloride-based resin compositionsalso need coloring resistance because color is important for resinmolded bodies used as building materials. In order to improve suchproperties as thermal stability and coloring resistance, chlorinatedvinyl chloride-based resins are usually mixed with a thermal stabilizerbefore melt molding.

Conventionally used thermal stabilizers contain a heavy metal such aslead, cadmium, or tin. As concerns have arisen about the toxicity or theadverse effects on the environment of heavy metals, thermal stabilizersor resin molded products free of highly toxic heavy metals, such aslead, have been proposed. For example, Patent Literature 1 discloses astabilized halogen-containing resin composition that contains ahalogen-containing resin and a composite of acid clay and/or activatedclay with a calcium hydroxide compound represented by the formulaCa_(1-x-y)M²⁺ _(x)Al_(y)(OH)₂ (where M²⁺ is a divalent such as Mg, Zn,or Cu; and x and y are respectively within the ranges of 0≦x<0.4 and0≦y<0.1).

However, even if a chlorinated vinyl chloride resin is contained with acomposite of acid clay and/or activated clay with a calcium hydroxidecompound, the stability is insufficient.

CITATION LIST Patent Literature

Patent Literature 1: JP 2008-214466 A

SUMMARY OF INVENTION Technical Problem

The present invention aims to provide a resin composition for moldingwhich contains a chlorinated vinyl chloride-based resin and hasexcellent thermal stability, and to provide a molded body thereof.

Solution to Problem

One aspect of the present invention provides a resin composition formolding, including a chlorinated vinyl chloride-based resin, a thermalstabilizer, and a polyalcohol and/or a partial ester of a polyalcohol,the chlorinated vinyl chloride-based resin having a chlorine content of65% by weight or more and less than 72% by weight, the chlorinated vinylchloride-based resin having, based on the total number of moles of astructural unit (a) —CCl₂—, a structural unit (b) —CHCl—, and astructural unit (c) —CH₂—, a proportion of the structural unit (a) of17.5 mol % or less, a proportion of the structural unit (b) of 46.0 mol% or more, and a proportion of the structural unit (c) of 37.0 mol % orless, the thermal stabilizer containing at least one of a compoundrepresented by the formula Ca_(1-x)Zn_(x)(OH)₂ where x satisfies theinequality 0<x<1 and a compound represented by the formulaCa_(1-y)Zn_(y)O where y satisfies the inequality 0<y<1; and a moldedbody of the resin composition.

Advantageous Effects of Invention

The present invention provides a resin composition for molding whichcontains a chlorinated vinyl chloride-based resin and has excellentthermal stability, and a molded body thereof.

The present invention provides a resin composition for molding which hasa suitable tensile strength, a suitable tensile modulus, a suitablethermal deformation temperature, and excellent mechanical properties,and a molded body thereof.

DESCRIPTION OF EMBODIMENTS

The resin composition for molding of the present invention contains achlorinated vinyl chloride-based resin (hereinafter, referred to as“CPVC”), a thermal stabilizer, and a polyalcohol and/or a partial esterof a polyalcohol.

The CPVC has a chlorine content of 65% by weight or more and less than72% by weight. If the chlorine content is 65% by weight or more, theCPVC can have a practically effective heat resistance. If the chlorinecontent is less than 72% by weight, a practically appropriateproductivity of a chlorination reaction can be ensured, and themoldability of the resin composition for molding containing the CPVC canbe sufficient.

The CPVC is obtained by chlorination of a vinyl chloride-based resin(PVC). The CPVC is a highly chlorinated resin with a chlorine content ofabout 65% by weight or more and less than 72% by weight. The chlorinecontent of the CPVC can be measured in accordance with JIS K 7229.

The CPVC contains a structural unit (a) —CCl₂—, a structural unit (b)—CHCl—, and a structural unit (c) —CH₂—.

The proportion of the structural unit (a) is 17.5 mol % or less based onthe total number of moles of the structural units (a), (b), and (c). Theproportion of the structural unit (a) is preferably 2.0 mol % or moreand 16.0 mol % or less.

The proportion of the structural unit (b) is 46.0 mol % or more based onthe total number of moles of the structural units (a), (b), and (c). Theproportion of the structural unit (b) is preferably 53.5 mol % or more,more preferably 58.0 mol % or more and 70.0 mol % or less.

The proportion of the structural unit (c) is 37.0 mol % or less based onthe total number of moles of the structural units (a), (b), and (c). Theproportion of the structural unit (c) is preferably 35.8 mol % or less,more preferably 1.0 mol % or more and 30.5 mol % or less.

Such a CPVC can have high thermal stability as well as good moldability.

The mole ratio of the structural units (a), (b) and (c) in the molecularstructure of the CPVC reflects the sites to which chlorine is introducedin chlorination of a PVC. Ideally, a PVC before chlorination containsabout 0 mol % of the structural unit (a), about 50.0 mol % of thestructural unit (b), and about 50.0 mol % of the structural unit (c).Chlorination reduces the proportion of the structural unit (c) andincreases the proportions of the structural unit (b) and the structuralunit (a). If the proportion of unstable structural units (a) with largesteric hindrance excessively increases, or if chlorinated sites andnon-chlorinated sites are unevenly distributed in the same CPVCparticle, the non-uniformity of the state of chlorination increases. Theincrease in the non-uniformity significantly impairs the thermalstability of the CPVC. The CPVC with a proportion of the structural unit(a) of 17.5 mol % or less, a proportion of the structural unit (b) of46.0 mol % or more, and a proportion of the structural unit (c) of 37.0mol % or less has high uniformity and exhibits good thermal stability.

The mole ratio of the structural units (a), (b), and (c) in themolecular structure of the CPVC can be measured by analyzing themolecular structure by NMR. The NMR analysis can be performed inaccordance with the method described in R. A. Komoroski, R. G. Parker,J. P. Shocker, Macromolecules, 1985, 18, 1257-1265.

The PVC may be a vinyl chloride homopolymer, a copolymer of a vinylchloride monomer and a monomer having an unsaturated bondcopolymerizable with a vinyl chloride monomer, or a graft copolymercontaining a polymer graft-copolymerized with a vinyl chloride monomer.These polymers may be used alone, or in combination of two or morethereof.

Examples of the monomer having an unsaturated bond copolymerizable witha vinyl chloride monomer include α-olefins such as ethylene, propylene,and butylene; vinyl esters such as vinyl acetate and vinyl propionate;vinyl ethers such as butyl vinyl ether and cetyl vinyl ether;(meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate,butyl acrylate, and phenyl methacrylate; aromatic vinyls such as styreneand α-methylstyrene; vinyl halides such as vinylidene chloride andvinylidene fluoride; N-substituted maleimides such as N-phenyl maleimideand N-cyclohexyl maleimide. One or two or more thereof may be used.

The polymer to be graft-copolymerized with vinyl chloride may be anyplymer that can be graft-copolymerized with vinyl chloride. Examplesthereof include ethylene-vinyl acetate copolymers, ethylene-vinylacetate-carbon monoxide copolymers, ethylene-ethyl acrylate copolymers,ethylene-butyl acrylate-carbon monoxide copolymers, ethylene-methylmethacrylate copolymers, ethylene-propylene copolymers,acrylonitrile-butadiene copolymers, polyurethane, chlorinatedpolyethylene, and chlorinated polypropylene. These may be used alone, orin combination of two or more thereof.

The PVC may have any average degree of polymerization. The averagedegree of polymerization is preferably within the usual range of 400 to3000. The average degree of polymerization is more preferably 600 to1500. The average degree of polymerization can be measured in accordancewith JIS K 6720-2:1999.

The PVC can be polymerized by any method. A conventionally known methodmay be used, such as aqueous suspension polymerization, bulkpolymerization, solution polymerization, or emulsion polymerization.

In the CPVC molecular structure, a PVC portion which is not chlorinatedis represented as —CH₂—CHCl—. This portion herein is referred to as “VCunit”. In the CPVC used in the present invention, the amount of asequence of four or more VC units in the molecular structure ispreferably 30.0 mol % or less. As used herein, the term “sequence offour or more VC units” means a portion consisting of four or more VCunits joined in series.

The VC units present in the CPVC can be a starting point ofdehydrochlorination. VC units joined in series tend to cause a series ofdehydrochlorination reactions called “zipper reaction”. The greater theamount of the sequence of four or more VC units is, the more likelydehydrochlorination is to occur and the lower the thermal stability ofthe CPVC is. The amount of the sequence of four or more VC units ispreferably 30.0 mol % or less, more preferably 28.0 mol % or less, stillmore preferably 18.0 mol % or less, particularly preferably 16.0 mol %or less.

The amount of the sequence of four or more VC units in the molecularstructure can be measured by the above-mentioned molecular structureanalysis by NMR.

If the CPVC used in the present invention has a chlorine content of 65%by weight or more and less than 69% by weight, the CPVC preferably has aUV absorbance at 216 nm of 0.8 or less. If the CPVC has a chlorinecontent of 69% by weight or more and less than 72% by weight, the CPVCpreferably has a UV absorbance at 216 nm of 8.0 or less. In anultraviolet absorption spectrum, the wavelength of 216 nm is thewavelength at which —CH═CH—C(═O)— and —CH═CH—CH═CH—, heterologousstructures in the CPVC, show absorption.

The heterologous structures in the molecular chain after a chlorinationreaction can be quantified from the UV absorbance of the CPVC and thusused as an index of the thermal stability. In the molecular structure ofthe CPVC, a chlorine atom attached to carbon next to a doubly bondedcarbon is unstable. This chlorine atom acts as a starting point ofdehydrochlorination. Accordingly, the greater the UV absorbance at 216nm is, the more likely dehydrochlorination is to occur and the lower thethermal stability is. If the CPVC has a chlorine content of 65% byweight or more and less than 69% by weight and a UV absorbance of morethan 0.8, the heterologous structures in the molecular chain have alarge influence, reducing the thermal stability. If the CPVC has achlorine content of 69% by weight or more and less than 72% by weightand a UV absorbance of more than 8.0, the heterologous structures in themolecular chain have a large influence, reducing the thermal stability.

If the CPVC used in the present invention has a chlorine content of 65%by weight or more and less than 69% by weight, the time required for theamount of dehydrochlorination from the CPVC at 190° C. to reach 7000 ppmis preferably 60 seconds or longer. If the CPVC has a chlorine contentof 69% by weight or more and less than 72% by weight, the time ispreferably 100 seconds or longer.

CPVCs thermally decompose at high temperatures, generating HCl gas.Generally, as the degree of chlorination of a CPVC increases, the amountof VC units decreases and thus the amount of dehydrochlorination tendsto decrease. However, as the degree of chlorination increases,non-uniform chlorination and the amount of heterologous structuresincrease, reducing the thermal stability. Measurement of the amount ofdehydrochlorination thus enables analysis of the non-uniformchlorination and an increase in the amount of heterologous structures.For example, the time required for the amount of dehydrochlorinationfrom the CPVC at 190° C. to reach 7000 ppm can be used as an index ofthe thermal stability. The shorter the time is, the lower the thermalstability is.

If the chlorine content is 65% by weight or more and less than 69% byweight and the time is shorter than 60 seconds, the thermal stability issignificantly impaired. Thus, if the chlorine content is 65% by weightor more and less than 69% by weight, the time is preferably 60 secondsor longer, more preferably 70 seconds or longer, particularly preferably80 seconds or longer. If the chlorine content is 69% by weight or moreand less than 72% by weight and the time is shorter than 100 seconds,the thermal stability is significantly low. If the chlorine content is69% by weight or more and less than 72% by weight, the time ispreferably 100 seconds or longer, more preferably 120 seconds or longer,particularly preferably 140 seconds or longer.

The time it takes for the amount of dehydrochlorination at 190° C. toreach 7000 ppm can be measured as follows. One gram of the chlorinatedvinyl chloride resin is put in a test tube. The resin is heated at 190°C. using an oil bath, and the generated HCl gas is recovered. The HClgas thus recovered is dissolved in 100 mL of ion-exchanged water,followed by measuring the pH. The HCl concentration (ppm) (i.e., howmany grams of HCl are generated per 1,000,000 g of the chlorinated vinylchloride resin) is calculated based on the pH. The time it takes for theHCl concentration to reach 7000 ppm is measured.

The resin composition for molding of the present invention contains apolyalcohol and/or a partial ester of a polyalcohol.

Examples of the polyalcohol include mannitol, xylitol, sorbitol,trimethylolpropane, pentaerythritol, dipentaerythritol,tripentaerythritol, and glycerol.

The partial ester of a polyalcohol refers to an ester in which at leastone of the hydroxyl groups in the polyalcohol is not esterified andremains as a hydroxyl group. The use of a partial ester of a polyalcoholcan improve dispersibility in CPVC. The partial ester of a polyalcoholcan be obtained by reacting at least one of these polyalcohols with atleast one mono- or polycarboxylic acid.

Whether an ester is a partial ester of a polyalcohol can be confirmed bymeasuring the hydroxy value of the molecule in accordance with JIS K0070(1992), for example.

Examples of the mono- or polycarboxylic acid constituting the partialester of a polyalcohol include monocarboxylic acids such as acetic acid,propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid,caprylic acid, neodecanoic acid, 2-ethylhexanoic acid, pelargonic acid,capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristicacid, palmitic acid, isostearic acid, stearic acid, 1,2-hydroxystearicacid, behenic acid, montanic acid, benzoic acid, monochlorobenzoic acid,p-t-butylbenzoic acid, dimethylhydroxybenzoic acid,3,5-di-tert-butyl-4-hydroxybenzoic acid, toluic acid, dimethylbenzoicacid, ethylbenzoic acid, cumic acid, n-propylbenzoic acid, aminobenzoicacid, N,N-dimethylbenzoic acid, acetoxybenzoic acid, salicylic acid,p-t-octylsalicylic acid, oleic acid, elaidic acid, linoleic acid,linolenic acid, thioglycolic acid, mercaptopropionic acid, andoctylmercaptopropionic acid, and dicarboxylic acids such as oxalic acid,malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid,suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalicacid, terephthalic acid, oxyphthalic acid, chlorophthalic acid,aminophthalic acid, maleic acid, fumaric acid, citraconic acid,mesaconic acid, itaconic acid, aconitic acid, and thiodipropionic acid.Adipic acid is particularly preferred.

Among the polyalcohols and the partial esters of polyalcohols obtainedfrom mono- or polycarboxylic acids, pentaerythritol adipate,dipentaerythritol adipate, and dipentaerythritol are preferred.

In the resin composition for molding of the present invention, the lowerlimit of the total amount of the polyalcohol and the partial ester of apolyalcohol is preferably 0.05 parts by weight, more preferably 0.1parts by weight based on 100 parts by weight of the chlorinated vinylchloride-based resin. The upper limit thereof is preferably 3 parts byweight, more preferably 2 parts by weight. If the resin compositioncontains the polyalcohol and/or the partial ester of a polyalcohol in atotal amount in this range, stability can be improved.

The lower limit of the total amount of the polyalcohol and the partialester of a polyalcohol is preferably 1 part by weight, more preferably 2parts by weight, still more preferably 3.5 parts by weight based on 100parts by weight of the thermal stabilizer. The upper limit thereof ispreferably 150 parts by weight, more preferably 120 parts by weight,still more preferably 20 parts by weight.

The resin composition for molding of the present invention contains athermal stabilizer.

The thermal stabilizer contains at least one of a compound representedby the formula Ca_(1-x)Zn_(x)(OH)₂ (where x satisfies the inequality0<x<1) and a compound represented by the formula Ca_(1-y)Zn_(y)O (wherey satisfies the inequality 0<y<1). In the formulae, x is preferably 0.1or greater and 0.5 or less, and y is preferably 0.1 or greater and 0.5or less.

In the resin composition for molding of the present invention, the lowerlimit of the amount of the thermal stabilizer is preferably 0.4 parts byweight, more preferably 0.7 parts by weight based on 100 parts by weightof the chlorinated vinyl chloride-based resin. The upper limit thereofis preferably 10 parts by weight, more preferably 6 parts by weight. Ifthe resin composition contains the thermal stabilizer in an amount inthis range, the thermal stability can be further improved and the moldedbody can maintain its good appearance.

The thermal stabilizer is typically in the form of particles with anaverage secondary particle size of 0.1 to 3 μm.

The resin composition for molding of the present invention preferablyfurther contains a stabilizing aid. If the resin composition contains astabilizing aid, the thermal stability can be further improved.

Examples of the stabilizing aid include organic acid salts, epoxycompounds such as epoxidized soybean oil, epoxidized linseed oil,epoxidized tetrahydrophthalate, and epoxidized polybutadiene,organophosphorus compounds, phosphorous acid esters, phosphoric acidesters, antioxidants, metal hydroxides such as calcium hydroxide andsodium hydroxide, sodium adipate, hydrotalcite, and zeolite. These maybe used alone, or in combination of two or more thereof. Preferredstabilizing aids are organic acid salts, sodium adipate, andhydrotalcite.

Examples of the organic acid salts include sodium salts, calcium salts,magnesium salts, and potassium salts of organic acids. Examples of theorganic acids include monovalent carboxylic acids such as acetic acid,propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid,caprylic acid, neodecanoic acid, 2-ethylhexanoic acid, pelargonic acid,capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristicacid, palmitic acid, isostearic acid, stearic acid, 1,2-hydroxystearicacid, behenic acid, montanic acid, benzoic acid, monochlorobenzoic acid,p-t-butylbenzoic acid, dimethylhydroxybenzoic acid,3,5-di-tert-butyl-4-hydroxybenzoic acid, toluic acid, dimethylbenzoicacid, ethylbenzoic acid, cumic acid, n-propylbenzoic acid, aminobenzoicacid, N,N-dimethylbenzoic acid, acetoxybenzoic acid, salicylic acid,p-t-octylsalicylic acid, oleic acid, elaidic acid, linoleic acid,linolenic acid, thioglycolic acid, mercaptopropionic acid, andoctylmercaptopropionic acid, divalent carboxylic acids such as oxalicacid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelicacid, suberic acid, azelaic acid, sebacic acid, phthalic acid,isophthalic acid, terephthalic acid, oxyphthalic acid, chlorophthalicacid, aminophthalic acid, maleic acid, fumaric acid, citraconic acid,mesaconic acid, itaconic acid, aconitic acid, and thiodipropionic acid,monoesters or monoamide compounds thereof, and di- or triester compoundsof trivalent or tetravalent carboxylic acids such as hemimellitic acid,trimellitic acid, mellophanic acid, pyromellitic acid, and melliticacid. Here, all the hydroxy groups in the alcohol component as amaterial of the esters are esterified.

In order to improve initial coloring properties, the stabilizing aidpreferably contains a higher fatty acid salt as an organic acid salt.

Any higher fatty acid can be used. Examples thereof include monovalentcarboxylic acids such as acetic acid, propionic acid, butyric acid,valeric acid, caproic acid, enanthic acid, caplyric acid, neodecanoicacid, 2-ethylhexanoic acid, pelargonic acid, capric acid, undecanoicacid, lauric acid, tridecanoic acid, myristic acid, palmitic acid,isostearic acid, stearic acid, 1,2-hydroxystearic acid, behenic acid,montanic acid, benzoic acid, monochlorobenzoic acid, p-t-butylbenzoicacid, dimethylhydroxybenzoic acid, 3,5-di-tert-butyl-4-hydroxybenzoicacid, toluic acid, dimethylbenzoic acid, ethylbenzoic acid, cumic acid,n-propylbenzoic acid, aminobenzoic acid, N,N-dimethylbenzoic acid,acetoxybenzoic acid, salicylic acid, p-t-octylsalicylic acid, oleicacid, elaidic acid, linoleic acid, linolenic acid, thioglycolic acid,mercaptopropionic acid, and octylmercaptopropionic acid, oxalic acid,malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid,suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalicacid, terephthalic acid, oxyphthalic acid, chlorophthalic acid,aminophthalic acid, maleic acid, fumaric acid, citraconic acid,mesaconic acid, itaconic acid, aconitic acid, and thiodipropionic acid.In particular, stearic acid, 1,2-hydroxystearic acid, lauric acid,palmitic acid, myristic acid, behenic acid, and montanic acid arepreferred.

Examples of the metal component of the higher fatty acid salt includezinc, magnesium, calcium, lithium, and barium. In particular, zinc andmagnesium are preferred, and zinc is still more preferred.

The lower limit of the amount of the higher fatty acid salt to be addedis preferably 0.01 parts by weight, more preferably 0.05 parts by weightbased on 100 parts by weight of the CPVC. The upper limit thereof ispreferably 5.0 parts by weight, more preferably 3.0 parts by weight.

The resin composition for molding of the present invention is preferablyfree of β-diketone. Conventional thermal stabilizers contain β-diketonein order to improve the thermal stability. If a thermal stabilizercontaining β-diketone is used, the molded body of the resin compositionproduced by extrusion molding or injection molding tends to haveimpaired appearance. For example, the molded body has, on its surface,yellow to red-brown streaks with a width of about 0.1 to 1 mm parallelto the direction of the flow of resin. Such a molded body with impairedappearance is a defective product. In particular, use of a die that hasbeen used for a long time tends to cause such a defective product. Theresin composition of the present invention for molding can exhibitexcellent thermal stability without a thermal stabilizer containingβ-diketone.

The resin composition for molding according to the present invention,which has the above-described features, can have excellent thermalstability.

Another aspect of the present invention provides a molded body moldedfrom the resin composition for molding. The molded body, similarly tothe resin composition for molding, has excellent thermal stability. Themolded body also has good appearance. The molded body can be suitablyused in applications such as building materials, plumbing materials, andhousing materials.

The following will describe methods for producing the resin compositionfor molding and the molded body.

A method for producing the resin composition for molding includes: thestep of preparing a chlorinated vinyl chloride-based resin, the stepincluding suspending a vinyl chloride-based resin in an aqueous mediumin a reaction container to prepare a suspension, introducing chlorine inthe reaction container, and heating the suspension to chlorinate thevinyl chloride-based resin; and the step of mixing the chlorinated vinylchloride-based resin with a thermal stabilizer and a polyalcohol and/ora partial ester of a polyalcohol, the thermal stabilizer being at leastone of a compound represented by the formula Ca_(1-x)Zn_(x)(OH)₂ where xsatisfies the inequality 0<x<1 and a compound represented by the formulaCa_(1-y)Zn_(y)O where y satisfies the inequality 021 y<1.

The reaction container to be used in the chlorination reaction may be,for example, a commonly used container such as a glass-lined stainlesssteel reaction container or a titanium reaction container.

The method for suspending a vinyl chloride-based resin in an aqueousmedium to prepare a suspension is not limited. A cake-like PVC obtainedby removing monomers from a polymerized PVC may be used, or a dried PVCmay be resuspended in an aqueous medium. Alternatively, a suspension maybe used which is obtained by removing substances undesirable for achlorination reaction from the polymerization system. Preferably, acake-like PVC obtained by removing monomers from a polymerized PVC isused.

The aqueous medium may be, for example, ion exchange-treated pure water.The amount of the aqueous medium is not limited. The amount is commonlypreferably 2 to 10 parts by weight based on 100 parts by weight of PVC.

Chlorine to be introduced to the reaction container may be either liquidchlorine or gaseous chlorine. The use of liquid chlorine is efficientbecause a large amount of chlorine can be charged in a short period oftime. Chlorine may be added during the reaction in order to control thepressure or to supply chlorine. In this case, in addition to liquidchlorine, gaseous chlorine may be appropriately injected. It ispreferred to use chlorine from a cylinder after purging 5 to 10% byweight of chlorine therein.

The gauge pressure in the reaction container is not limited. It ispreferred that the gauge pressure is in the range of 0.3 to 2 MPabecause a higher chlorine pressure allows chlorine to more easilypenetrate inside PVC particles.

After chlorine is introduced, the suspension is heated to chlorinate thevinyl chloride-based resin. Thus, a chlorinated vinyl chloride-basedresin can be obtained. Heating excites bonds in the PVC and chlorine,thus promoting chlorination. The chlorination is performed withoutultraviolet irradiation. In the case of a chlorination reaction byultraviolet irradiation, the magnitude of light energy needed tochlorinate a PVC greatly depends on the distance between the PVC and thelight source. Accordingly, the surface and the inside of the PVCparticles receive different amounts of energy, causing non-uniformchlorination. This results in a CPVC with low uniformity. Chlorinationby heating without ultraviolet irradiation enables more uniformchlorination, providing a CPVC with high uniformity.

The heating temperature is preferably within the range of 70° C. to 140°C. If the temperature is too low, the chlorination rate is reduced. Ifthe temperature is too high, a dehydrochlorination reaction occurssimultaneously with a chlorination reaction, resulting in a coloredCPVC. The heating temperature is more preferably within the range of100° C. to 135° C. Any heating method may be used. Examples thereofinclude heating from the reaction container wall by an external jacketmethod.

Hydrogen peroxide is preferably added to the suspension in thechlorination reaction. The addition of hydrogen peroxide can increasethe rate of chlorination. Preferably, 0.0005 to 0.05 parts by weight ofhydrogen oxide based on 100 parts by weight of the PVC is added everyhour of reaction time. If the amount is too small, the effect ofincreasing the rate of chlorination may not be obtained. If the amountis too large, the thermal stability of the CPVC may decrease.

If hydrogen peroxide is added, the rate of chlorination increases, andthus the heating temperature can be relatively low. For example, theheating temperature may be within the range of 65° C. to 110° C.

In the chlorination, the chlorine consumption rate after the chlorinecontent reaches a value that is five percentage points by weight lowerthan the final chlorine content is controlled to be in the range of0.010 to 0.015 kg/PVC-Kg·5 min. The chlorine consumption rate after thechlorine content reaches a value that is three percentage points byweight lower than the final chlorine content is controlled to be in therange of 0.005 to 0.010 kg/PVC-Kg·5 min. As used herein, the term“chlorine consumption rate” refers to the amount of chlorine consumedper kilogram of the material PVC in five minutes.

The CPVC produced by chlorination by the above method can have a finalchlorine content of 65% by weight or more and less than 72% by weight.The CPVC also can have, based on the total number of moles of thestructural unit (a) —CCl₂—, the structural unit (b) —CHCl—, and thestructural unit (c) —CH₂—, a proportion of the structural unit (a) of17.5 mol % or less, a proportion of the structural unit (b) of 46.0 mol% or more, and a proportion of the structural unit (c) of 37.0 mol % orless. The CPVC also can have low non-uniformity in the state ofchlorination and excellent thermal stability.

A molded body can be obtained by mixing the obtained chlorinated vinylchloride-based resin with a thermal stabilizer and molding the resultingmixture. The molding method may be any conventionally known productionmethod, such as extrusion molding or injection molding.

The thermal stabilizer may contain other component(s).

In the production process, the CPVC may be optionally mixed withadditives such as a stabilizing aid, a lubricant, a processing aid, animpact modifier, a heat resistance improver, an antioxidant, anultraviolet absorber, a light stabilizer, filler, thermoplasticelastomer, or pigment. The addition of a stabilizing aid can furtherimprove the thermal stability of the molded body.

Any method may be used for mixing the thermal stabilizer and otheradditives with the CPVC. Examples thereof include hot blending and coldblending.

Any antioxidant may be used. Examples thereof include phenolicantioxidants, phosphoric acid antioxidants, sulfur antioxidants, andamine antioxidants. These maybe used alone, or in combination of two ormore thereof.

The hydrotalcite compound may be any conventionally known hydrotalcitecompound. The hydrotalcite compound may be a natural product or asynthetic product. Suitable hydrotalcite compounds include a double saltcompound composed of magnesium and aluminum.

The zeolite compound is an aluminosilicate of an alkali or alkalineearth metal that has a zeolite crystal structure. Examples thereofinclude A-type, X-type, Y-type, and P-type zeolites, mordenite,analcite, aluminosilicates in the sodalite group, clinoptilolite,erionite, and chabazite.

The hydrotalcite compounds and/or the zeolite compounds maybe usedalone, or used in combination thereof. If the amount thereof is small,the thermal stability effect is not exerted. If the amount is large,coloring may occur. The lower limit thereof is preferably 0 parts byweight, more preferably 0.05 parts by weight, still more preferably 0.1parts by weight based on 100 parts by weight of the CPVC. The upperlimit thereof is preferably 2.0 parts by weight, more preferably 1.2parts by weight, still more preferably 0.8 parts by weight.

Examples of the lubricant include internal lubricants and externallubricants. Internal lubricants are used to reduce the flow viscosity ofmolten resin in the molding process to prevent friction heating. Anyinternal lubricant may be used. Examples thereof include butyl stearate,lauryl alcohol, stearyl alcohol, stearic acid, and bisamide. These maybeused alone, or in combination of two or more thereof.

External lubricants are used to enhance slipping between molten resinand a metal surface in the molding process. Any external lubricant maybe used. Examples thereof include paraffin wax, polyolefin wax, esterwax, and montanic acid wax. These may be used alone, or in combinationof two or more thereof.

Any processing aid may be used. Examples thereof include acrylicprocessing aids such as alkyl acrylate-alkyl methacrylate copolymerswith a weight average molecular weight of 100,000 to 2,000,000. Anyacrylic processing aid may be used. Examples thereof include n-butylacrylate-methyl methacrylate copolymers and 2-ethylhexyl acrylate-methylmethacrylate-butyl methacrylate copolymers. These may be used alone, orin combination of two or more thereof.

Any impact modifier may be used. Examples thereof include methylmethacrylate-butadiene-styrene copolymers (MBS), chlorinatedpolyethylene, and acrylic rubber.

Any heat resistance improver may be used. Examples thereof includeα-methylstyrene resins, and N-phenylmaleimide resins.

Any light stabilizer may be used. Examples thereof include hinderedamine light stabilizers.

Any ultraviolet absorber may be used. Examples thereof include salicylicacid ester ultraviolet absorbers, benzophenone ultraviolet absorbers,benzotriazole ultraviolet absorbers, and cyanoacrylate ultravioletabsorbers.

Any filler may be used. Examples thereof include calcium carbonate andtalc.

Any pigment may be used. Examples thereof include organic pigments suchas azo pigments, phthalocyanine pigments, indanthrene pigments, and dyelake pigments; and inorganic pigments such as oxide pigments,sulfide/selenide pigments, and ferrocyanide pigments.

The molded body may contain a plasticizer in order to improve theprocessability in molding. The use of a plasticizer in a large amount isnot so preferable because it may reduce the thermal stability of themolded body. Any plasticizer may be used. Examples thereof includedibutyl phthalate, di-2-ethylhexyl phthalate, and di-2-ethylhexyladipate.

The molded body may contain a thermoplastic elastomer in order toimprove workability. Any thermoplastic elastomer may be used. Examplesthereof include vinyl chloride thermoplastic elastomers such asacrylonitrile-butadiene (NBR) copolymers, ethylene-vinyl acetate (EVA)copolymers, ethylene-vinyl acetate-carbon monoxide (EVACO) copolymers,vinyl chloride-vinyl acetate copolymers, and vinyl chloride-vinylidenechloride copolymers, and styrene thermoplastic elastomers, olefinthermoplastic elastomers, urethane thermoplastic elastomers, polyesterthermoplastic elastomers, and polyamide thermoplastic elastomers. Thesethermoplastic elastomers may be used alone, or in combination of two ormore thereof.

The above methods can provide a resin composition for molding havingexcellent thermal stability and a molded body molded from the resincomposition.

EXAMPLES

The following will describe embodiments of the present invention withreference to examples. The present invention should not be limited tothe examples.

Example 1 Preparation of Chlorinated Vinyl Chloride Resin

A glass-lined reaction container with an internal volume of 300 L wascharged with 200 kg of ion-exchanged water and 56 kg of vinyl chlorideresin with an average degree of polymerization of 1000. The mixture wasstirred, and water was added to the reaction container, so that themixture was dispersed in the water. Subsequently, the temperature wasincreased to 90° C. while the pressure was reduced to remove oxygen inthe reaction container.

Then, chlorine was fed to the reaction container to achieve a partialpressure of chlorine of 0.4 MPa, and a chlorination reaction wasperformed while 0.2% by weight hydrogen peroxide was added at a rate of1 part by weight per hour (320 ppm/hour). The reaction was continueduntil the chlorine content of the chlorinated vinyl chloride resinreached 61% by weight. When the chlorine content of the chlorinatedvinyl chloride resin reached 61% by weight (five percentage points byweight lower than the final chlorine content), the addition amount of0.2% by weight hydrogen peroxide was reduced to 0.1 parts by weight perhour (200 ppm/hour), and chlorination was allowed to proceed at anaverage chlorine consumption rate of 0.012 kg/PVC-kg·5 min. When thechlorine content reached 63% by weight (three percentage points byweight lower than the final chlorine content), the addition amount of0.2% by weight hydrogen peroxide was reduced to 150 ppm/per hour, andchlorination was allowed to proceed at an average chlorine consumptionrate of 0.008 kg/PVC-kg·5 min. In this manner, a chlorinated vinylchloride resin with a chlorine content of 65.6% by weight was obtained.

Preparation of Thermal Stabilizer

A compound of the formula Ca_(0.9)Zn_(0.1)(OH)₂ was prepared to be usedas a thermal stabilizer.

A beaker with a volume of 2 L was charged with 1 L of 1 mol/L Ca(OH)₂slurry. An amount of 500 mL of a 0.2 mol/L aqueous solution of Zn(NO₃)₂was added thereto with stirring at 30° C. The reaction product wasfiltered and washed with water. Thereafter, the resulting cake wasdispersed in 1 L of water. The dispersion was heated to about 80° C.With stirring, a solution of 1 g of sodium stearate in 100 mL of warmwater (about 80° C.) was added to the dispersion, whereby surfacetreatment was performed. The resulting product was filtered and washedwith water, and then dried. The dried product was subjected to achemical composition analysis by ICP emission spectrometry. The chemicalcomposition analysis confirmed that the obtained compound wasCa_(0.9)Zn_(0.1)(OH)₂.

Preparation of Chlorinated Vinyl Chloride-Based Resin Molded Body)

A chlorinated vinyl chloride resin composition was prepared using theobtained chlorinated vinyl chloride resin, the thermal stabilizer, and apartial ester of a polyalcohol. The thermal stabilizer was used in aproportion of 3.0 parts by weight, and the polyalcohol was used in aproportion of 0.3 parts by weight, each based on 100 parts by weight ofthe chlorinated vinyl chloride resin. The partial ester of a polyalcoholused was dipentaerythritol adipate. Additionally, 0.3 parts by weight ofsodium adipate (“B-NT/7222” available from REAGENS) as a stabilizingaid, 5 parts by weight of MBS (“Kane Ace M-511” available from KanekaCorporation) as an impact modifier, 2 parts by weight of a polyethylenelubricant (“Hiwax220MP” available from Mitsui Chemicals, Inc.), and 0.3parts by weight of a fatty acid ester lubricant (“LOXIOL G-32” availablefrom Emery Oleochemicals Japan Ltd.) were used. These components wereuniformly mixed in a super mixer, whereby a chlorinated vinyl chlorideresin composition was obtained.

A measurement in accordance with JIS K 0070 (1992) confirmed that thedipentaerythritol adipate had a hydroxy value of 900, and that a part ofthe hydroxy groups was not esterified.

The obtained chlorinated vinyl chloride resin composition was fed to aconical counter-rotating twin-screw extruder (“SLM-50” available fromOsada Seisakusho) with a diameter of 50 mm. A pipe-shaped molded bodywith an outer diameter of 20 mm and a thickness of 3 mm was prepared ata resin temperature of 205° C.

Example 2

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the amount of the thermalstabilizer was changed as shown in Table 1.

Example 3

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that a compound of the formulaCa_(0.9)Zn_(0.1)O was used as a thermal stabilizer instead of a compoundof the formula Ca_(0.9)Zn_(0.1)(OH)₂.

Example 4

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the amount ofdipentaerythritol adipate was changed as shown in Table 1.

Example 5

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1, and that 0.5 parts by weight ofhydrotalcite was used as a stabilizing aid instead of 0.3 parts byweight of sodium adipate.

Example 6

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1, that a compound of the formulaCa_(0.5)Zn_(0.5)(OH)₂ was used as a thermal stabilizer instead of acompound of the formula Ca_(0.9)Zn_(0.1)(OH)₂, and that 0.5 parts byweight of hydrotalcite was used as a stabilizing aid instead of 0.3parts by weight of sodium adipate.

Example 7

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1, that 7.0 parts by weight of a compoundof the formula Ca_(0.9)Zn_(0.1)O was used as a thermal stabilizerinstead of 3.0 parts by weight of a compound of the formulaCa_(0.9)Zn_(0.1)(OH)₂, that dipentaerythritol was used instead ofdipentaerythritol adipate, and that 0.5 parts by weight of hydrotalcitewas used as a stabilizing aid instead of 0.3 parts by weight of sodiumadipate.

Example 8

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1, and that dipentaerythritol was usedinstead of dipentaerythritol adipate.

Example 9

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1, that 7.0 parts by weight of a compoundof the formula Ca_(0.5)Zn_(0.5)(OH)₂ was used as a thermal stabilizerinstead of 3.0 parts by weight of a compound of the formulaCa_(0.9)Zn_(0.1)(OH)₂, and that dipentaerythritol was used instead ofdipentaerythritol adipate.

Example 10

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1, that a compound of the formulaCa_(0.9)Zn_(0.1)O was used as a thermal stabilizer instead of a compoundof the formula Ca_(0.9)Zn_(0.1)(OH)₂, and that dipentaerythritol wasused instead of dipentaerythritol adipate.

Example 11

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1, and that dipentaerythritol was usedinstead of dipentaerythritol adipate.

Example 12

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the amount ofdipentaerythritol adipate was changed to 2.3 parts by weight.

Example 13

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that 0.3 parts by weight ofsodium adipate and 0.5 parts by weight of β-diketone were used incombination as stabilizing aids.

Example 14

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the amount of the thermalstabilizer was changed as shown in Table 1.

Example 15

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the amount of the thermalstabilizer was changed as shown in Table 1.

Example 16

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that 0.2 parts by weight ofdipentaerythritol adipate and 0.1 parts by weight of dipentaerythritolwere used instead of 0.3 parts by weight of dipentaerythritol adipate.

Example 17

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that pentaerythritol adipate wasused instead of dipentaerythritol adipate.

A measurement performed in the same manner as in Example 1 confirmedthat the pentaerythritol adipate had a hydroxy value of 880 and that apart of the hydroxy groups was not esterified.

Example 18

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that 0.3 parts by weight of zincstearate was used as a stabilizing aid.

Example 19

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that 4.0 parts by weight of zincstearate was used as a stabilizing aid.

Example 20

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that 0.3 parts by weight ofsodium adipate and 0.3 parts by weight of zinc stearate were used asstabilizing aids.

Comparative Example 1

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1.

Comparative Example 2

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1.

Comparative Example 3

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that a compound of the formulaCa_(0.0)Zn_(1.0)(OH)₂ was used as a thermal stabilizer instead of acompound of the formula Ca_(0.9)Zn_(0.1)(OH)₂.

Comparative Example 4

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that a compound of the formulaCa_(1.0)Zn_(0.0)(OH)₂ was used as a thermal stabilizer instead of acompound of the formula Ca_(0.9)Zn_(0.1)(OH)₂.

Comparative Example 5

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1, that a compound of the formulaCa_(0.5)Zn_(0.5)(OH)₂ was used as a thermal stabilizer instead of acompound of the formula Ca_(0.9)Zn_(0.1)(OH)₂, and thatdipentaerythritol adipate was not used.

Comparative Example 6

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the molecular structureproportion of the chlorinated vinyl chloride resin was changed as shownin Table 1.

Comparative Example 7

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1.

Comparative Example 8

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1.

Comparative Example 9

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that a calcium-zinc stabilizer(TMF-108J, available from Tokyo Fine Chemical Co., Ltd.) was used as athermal stabilizer instead of a compound of the formulaCa_(0.9)Zn_(0.1)(OH)₂.

Comparative Example 10

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the molecular structureproportion of the chlorinated vinyl chloride resin was changed as shownin Table 1, and that a calcium-zinc stabilizer (TMF-108J) was used as athermal stabilizer instead of a compound of the formulaCa_(0.9)Zn_(0.1)(OH)₂.

Comparative Example 11

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1, and that a calcium-zinc stabilizer(TMF-108J) was used as a thermal stabilizer instead of a compound of theformula Ca_(0.9)Zn_(0.1)(OH)₂.

Comparative Example 12

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the chlorine content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1, and that 0.3 parts by weight of sodiumadipate and 0.5 parts by weight of β-diketone were used in combinationas stabilizing aids.

Comparative Example 13

A chlorinated vinyl chloride resin and a molded body were prepared inthe same manner as in Example 1 except that the carbon content and themolecular structure proportion of the chlorinated vinyl chloride resinwere changed as shown in Table 1.

Analysis

The chlorine content, the UV absorbance, and the dehydrochlorinationtime of each of the chlorinated vinyl chloride resins according to theexamples and the comparative examples were measured. The amounts (mol %)of —CCl₂—, —CHCl—, and —CH₂— and the amount (mol %) of a sequence offour or more VC units were also measured by a molecular structureanalysis. The measurement methods are described below. Table 1 shows theresults.

<Chlorine Content Measurement>

The chlorine content was measured in accordance with JIS K 7229.

<Molecular Structure Analysis>

The measurement was performed in accordance with the NMR measurementmethod disclosed in R. A. Komoroski, R. G. Parker, J. P. Shocker,Macromolecules, 1985, 18, 1257-1265.

The NMR measurement was performed under the following conditions.

-   Device: FT-NMR (JNM-AL-300, available from JEOL Ltd.)-   Observed nucleus: 13C (complete proton decoupling)-   Pulse width: 90°-   PD: 2.4 sec-   Solvent: o-dichlorobenzene:deuterated benzene (C5D5)=3:1-   Sample concentration: about 20%-   Temperature: 110° C.-   Standard: The central signal of benzene was taken as 128 ppm.-   Number of accumulations: 20,000

<Measurement of UV Absorbance (216 Nm)>

The UV absorbance at 216 nm was measured under the following conditions.

-   Device: recording spectrophotometer (U-3500, available from Hitachi,    Ltd.)-   Solvent: THF-   Concentration: sample 20 mg/THF 25 mL . . . 800 ppm (Examples 1 to 7    and 12 to 19 and Comparative Examples 1, 3, 4, 6, and 8 to 13),-   sample 10 mg/THF 25 mL . . . 400 ppm (Examples 8 to 11 and    Comparative Examples 2, 5, and 7)

<Dehydrochlorination Time>

One gram of the obtained chlorinated vinyl chloride resin was put in atest tube and heated at 190° C. using an oil bath. Generated HCl gas wasrecovered and dissolved in 100 mL of ion-exchanged water. The pH wasmeasured. How many grams of HCl were generated per 1,000,000 g of thechlorinated vinyl chloride resin was calculated from the pH. The time ittook for this value to reach 7000 ppm was measured.

Evaluation

The static thermal stability, the dynamic thermal stability, and themechanical properties of the chlorinated vinyl chloride resins accordingto the examples and the comparative examples were measured. Theappearance of the molded bodies was observed. The measurement methodsare described below. Table 1 shows the results. Numbers without units inthe table are in parts by weight.

<Static Thermal Stability>

Each of the chlorinated vinyl chloride resin compositions according tothe examples and the comparative examples was fed into a roll mill withtwo 8-inch rolls. The resin composition was kneaded at 205° C. for threeminutes and formed into a sheet with a thickness of 1.0 mm. The obtainedsheet was heated in a gear oven at 200° C. The coloring initiation time(minutes) and the foaming or blackening time (minutes) were measured.The time at which yellowing started was taken as the coloring initiationtime. The time before foaming or blackening was taken as thefoaming/blackening time.

<Dynamic Thermal Stability>

Each of the chlorinated vinyl chloride resin compositions according tothe examples and the comparative examples was fed into a plastomill(“Labo PlastoMill” available from Toyo Seiki Seisaku-Sho, Ltd.) andkneaded at 50 rpm, 195° C., and a filling amount of 63 g. The gellingtime (seconds) was measured. The time from when kneading was started towhen the kneading torque reached its peak was taken as the gelling time.After gelling, kneading and heating were continued, and thedecomposition time (minutes) of the chlorinated vinyl chloride resin wasmeasured. The time from when kneading was started to when the kneadingtorque, which was stable after gelling, started to rise again was takenas the decomposition time.

<Mechanical Properties (Tensile Strength, Tensile Modulus, ThermalDeformation Temperature)>

Each of the chlorinated vinyl chloride resin compositions according tothe examples and the comparative examples was fed into a roll mill withtwo 8-inch rolls. The resin composition was kneaded at 205° C. for threeminutes and formed into sheets with a thickness of 1.0 mm. The obtainedsheets were layered on top of each other, preheated with a press at 205°C. for three minutes, and then pressurized for four minutes. Thus, apress plate with a thickness of 3 mm was obtained. A specimen was cutout from the obtained press plate by machine processing. The tensilestrength and the tensile modulus were measured using this specimen inaccordance with ASTM D638. The thermal deformation temperature was alsomeasured at a load of 186 N/cm² in accordance with ASTM D648. Thethermal deformation temperature was measured after the press plate wasannealed in a gear oven at 90° C. for 24 hours.

<Observation of Appearance of Molded Body>

Each of the pipe-shaped molded bodies according to the examples and thecomparative examples was air-cooled at room temperature for fiveminutes. Thereafter, the surface state was visually observed for thepresence or absence of bubbles, the presence or absence of streaks, andthe presence or absence of scorching (discoloration).

<Results>

The resin compositions according to Examples 1 to 15 exhibited higherthermal stability and higher mechanical properties than those accordingto the comparative examples. In the molded bodies according to Examples1 to 12, 14, and 16 to 20, almost no bubbles, streaks, or scorch wereobserved, showing that these molded bodies had better appearance thanthose according to the comparative examples.

In Example 12, the thermal deformation temperature was relatively low.This shows that a higher total amount of a polyalcohol and a partialester of a polyalcohol tends to lead to a lower thermal deformationtemperature.

Example 13 employed β-diketone as a stabilizing aid. In Example 13,streaks were observed in the appearance of the molded body. This showsthat the molded body containing β-diketone tends to have impairedappearance. The results of Examples 1 to 11 show that according to thepresent invention, sufficient thermal stability and mechanicalproperties can be obtained without β-diketone.

In Example 14, the thermal stability was a little lower than inExample 1. This shows that a thermal stabilizer content of 0.4 parts byweight or more leads to an even higher thermal stability.

In Example 15, the thermal stability was higher than in Example 1, butstreaks were observed in the appearance of the molded body. This showsthat a thermal stabilizer content of 10 parts by weight or less enablesboth high thermal stability and good appearance of the molded body.

TABLE 1 Example 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 ChlornatedChlorine content (% by weight) 65.6 65.6 65.6 65.6 68.3 68.3 68.3 70.670.6 70.6 71.8 65.6 65.6 65.6 65.6 65.6 65.6 vinyl Molecular —CCl₂— (mol%) 5.7 5.7 5.7 5.7 7.5 7.5 7.5 16.9 16.9 16.9 17.3 5.7 5.7 5.7 5.7 5.75.7 chloride structure —CHCl— (mol %) 60.1 60.1 60.1 60.1 65 65 65 55.155.1 55.1 58.9 60.1 60.1 60.1 60.1 60.1 60.1 resin proportion —CH₂— (mol%) 34.2 34.2 34.2 34.2 27.5 27.5 27.5 28.0 28.0 28.0 23.8 34.2 34.2 34.234.2 34.2 34.2 Sequence of four or more 26.4 26.4 26.4 26.4 23.6 23.623.6 15.9 15.9 15.9 13.9 26.4 26.4 26.4 26.4 26.4 26.4 VC units (mol %)UV absorbance (216 nm) 0.7 0.7 0.7 0.7 0.8 0.8 0.8 5.3 5.3 5.3 5.8 0.70.7 0.7 0.7 0.7 0.7 Dehydrochlorination time (seconds) 90 90 90 90 95 9595 148 148 148 160 90 90 90 90 90 90 Thermal Ca_(0.9)Zn_(0.1)(OH)₂ 3.07.0 — 3.0 3.0 — — 3.0 — — 3.0 3.0 3.0 0.3 11.0 3.0 3.0 stabilizerCa_(0.5)Zn0.5(OH)₂ — — — — — 3.0 — — 7.0 — — — — — — — —Ca_(0.9)Zn_(0.1)O — — 3.0 — — — 7.0 — — 3.0 — — — — — — —Ca_(1.0)Zn_(0.0)(OH)₂ — — — — — — — — — — — — — — — — —Ca_(0.0)Zn_(1.0)(OH)₂ — — — — — — — — — — — — — — — — — Calcium-zincstabilizer — — — — — — — — — — — — — — — — — Polyalcohol orDipentaerythrtol adipate 0.3 0.3 0.3 1.8 0.3 0.3 — — — — — 2.3 0.3 0.30.3 0.2 — partial ester Dipentaerythrtol — — — — — — 0.3 0.3 0.3 0.3 0.3— — — — 0.1 — thereof Pentaerythritol adipate — — — — — — — — — — — — —— — — 0.3 Stabilizing aid Sodium adipate 0.3 0.3 0.3 0.3 — — — 0.3 0.30.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Zinc stearate — — — — — — — — — — — — —— — — — Hydrotalcite — — — — 0.5 0.5 0.5 — — — — — — — — — — β diketone— — — — — — — — — — — — 0.5 — — — — Theremal Static Coloring initiationtime 40 50 40 40 40 50 50 40 50 40 40 40 40 40 60 40 40 stabilitythermal (minutes) evaluation stability Foaming/blackening time 100 100100 110 100 90 90 90 90 90 100 100 90 65 120 100 90 (minutes) DynamicGelling time (seconds) 102 96 95 95 87 93 89 94 97 94 95 93 89 85 110 9992 thermal Decomposition time 18 14 17 19 15 16 16 16 14 16 16 18 18 1235 18 14 stability (minutes) Mechanical Tensile strength (MPa) 55.5 55.855.5 53.5 58.4 59.7 61.3 62.0 61.4 62.7 62.2 52.3 54.4 55.1 52.2 55.055.8 properties Tensile modulus (MPa) 3050 2980 2730 2870 2750 2950 28303050 2870 2960 2950 2880 2710 2250 2690 3010 3100 Thermal deformationtemperature 109 106 105 105 113 115 114 125 122 124 127 99 108 110 107109 109 (° C.) Appearance of Foaming Absence Absence Absence AbsenceAbsence Absence Absence Absence Absence Absence Absence Absence AbsenceAbsence Absence Absence Absence molded body Streaks Absence AbsenceAbsence Absence Absence Absence Absence Absence Absence Absence AbsenceAbsence Presence Absence Presence Absence Absence Scorching AbsenceAbsence Absence Absence Absence Absence Absence Absence Absence AbsenceAbsence Absence Absence Absence Absence Absence Absence ExampleComparative Example 18 19 20 1 2 3 4 5 6 7 8 9 10 11 12 13 ChlorinatedChlorine content (% by weight) 65.6 65.6 65.6 62.9 73.4 65.6 65.6 70.665.6 70.6 56.8 65.6 65.6 56.8 56.8 62.9 vinyl Molecular —CCl₂— (mol %)5.7 5.7 5.7 5.1 19.7 5.7 5.7 16.9 8.8 18.1 0 5.7 8.8 0 0 0.7 chlorideproportion —CHCl— (mol %) 60.1 60.1 60.1 53.7 61.5 60.1 60.1 55.1 53.852.7 50 60.1 53.8 50 50 62.4 resin —CH₂— (mol %) 34.2 34.2 34.2 41.218.8 34.2 34.2 28.0 37.4 29.2 50 34.2 37.4 50 50 36.8 Sequence of fouror more 26.4 26.4 26.4 33.2 11.4 26.4 26.4 15.9 33.7 16.8 100 26.4 33.7100 100 33.2 VC units (mol %) UV absorbance (216 nm) 0.7 0.7 0.7 1.3 8.90.7 0.7 5.3 1.3 8.2 0 0.7 1.3 0 0 1.3 Dehydrochlorination time (seconds)90 90 90 55 65 90 90 148 52 96 20 90 52 20 20 55 ThermalCa_(0.9)Zn_(0.1)(OH)₂ 3.0 7.0 7.0 3.0 3.0 — — — 3.0 3.0 3.0 — — — 3.03.0 stabilizer Ca_(0.5)Zn_(0.5)(OH)₂ — — — — — — — 3.0 — — — — — — — —Ca_(0.9)Zn_(0.1)O — — — — — — — — — — — — — — — — Ca_(1.0)Zn_(0.0)(OH)₂— — — — — — 3.0 — — — — — — — — — Ca_(0.0)Zn_(1.0)(OH)₂ — — — — — 3.0 —— — — — — — — — — Calcium-zinc stabilizer — — — — — — — — — — — 0.3 0.30.3 — — Polyalcohol or Dipentaerythrtol adipate 0.3 0.3 0.3 0.3 0.3 0.30.3 0 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 partial ester Dipentaerythrtol — —— — — — — — — — — — — — — — thereof Pentaerythritol adipate — — — — — —— — — — — — — — — — Stabilizing aid Sodium adipate — — 0.3 0.3 0.3 0.30.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Zinc stearate 0.3 4.0 0.3 — — —— — — — — — — — — — Hydrotalcite — — — — — — — — — — — — — — — — βdiketone — — — — — — — — — — — — — — 0.5 — Theremal Static Coloringinitiation time 60 70 70 10 10 10 10 10 10 10 10 10 10 10 10 10stability thermal (minutes) evaluation stability Foaming/blackening time100 100 100 45 35 35 35 55 45 45 20 30 30 20 20 40 (minutes) DynamicGelling time (seconds) 110 114 112 87 94 100 100 100 94 97 71 95 95 7373 88 thermal Decomposition time 17 13 16 8 6 7 6 7 12 13 3 5 5 3 3 8stability (minutes) Mechanical Tensile strength (MPa) 55.1 54.9 55.151.0 65.2 55.9 54.3 62.6 54.6 61.0 44.3 54.3 55.1 45.1 45.2 50.9properties Tensile modulus (MPa) 2990 2960 2990 2880 2980 2950 2830 30602760 2880 2590 2800 2830 2590 2610 2820 Thermal deformation temperature109 106 109 97 132 106 108 122 109 121 87 107 107 89 88 97 (° C.)Appearance of Foaming Absence Absence Absence Absence Presence PresencePresence Presence Absence Absence Absence Presence Presence AbsenceAbsence Absence molded body Streaks Absence Absence Absence AbsenceAbsence Absence Absence Absence Absence Absence Absence Absence AbsenceAbsence Presence Absence Scorching Absence Absence Absence AbsencePresence Presence Presence Presence Presence Presence Absence PresencePresence Absence Absence Absence

INDUSTRIAL APPLICABILITY

The present invention provides a resin composition for moldingcontaining a chlorinated vinyl chloride-based resin and a molded bodythereof.

1. A resin composition for molding, comprising: a chlorinated vinylchloride-based resin; a thermal stabilizer; and a polyalcohol and/or apartial ester of a polyalcohol, the chlorinated vinyl chloride-basedresin having a chlorine content of 65% by weight or more and less than72% by weight, the chlorinated vinyl chloride-based resin having, basedon the total number of moles of a structural unit (a) —CCl₂—, astructural unit (b) —CHCl—, and a structural unit (c) —CH₂—, aproportion of the structural unit (a) of 17.5 mol % or less, aproportion of the structural unit (b) of 46.0 mol % or more, and aproportion of the structural unit (c) of 37.0 mol % or less, the thermalstabilizer containing at least one of a compound represented by theformula Ca_(1-x)Zn_(x)(OH)₂ where x satisfies the inequality 0<x<1 and acompound represented by the formula Ca_(1-y)Zn_(y)O where y satisfiesthe inequality 0<y<1.
 2. The resin composition for molding according toclaim 1, wherein the chlorinated vinyl chloride-based resin has achlorine content of 65% by weight or more and less than 69% by weight.3. The resin composition for molding according to claim 1, wherein thechlorinated vinyl chloride-based resin has a chlorine content of 69% byweight or more and less than 72% by weight.
 4. The resin composition formolding according to claim 1, wherein the chlorinated vinylchloride-based resin has, based on the total number of moles of thestructural unit (a) —CCl₂—, the structural unit (b) —CHCl—, and thestructural unit (c) —CH₂—, a proportion of the structural unit (b) of58.0 mol % or more and a proportion of the structural unit (c) of 35.8mol % or less.
 5. The resin composition for molding according to claim1, wherein the chlorinated vinyl chloride-based resin has a UVabsorbance at 216 nm of 0.8 or less.
 6. The resin composition formolding according to claim 1, wherein the chlorinated vinylchloride-based resin has a UV absorbance at 216 nm of 8.0 or less. 7.The resin composition for molding according to claim 1, wherein timerequired for the amount of dehydrochlorination from the chlorinatedvinyl chloride-based resin at 190° C. to reach 7000 ppm is 60 seconds orlonger.
 8. The resin composition for molding according to claim 1,wherein time required for the amount of dehydrochlorination from thechlorinated vinyl chloride-based resin at 190° C. to reach 7000 ppm is100 seconds or longer.
 9. The resin composition for molding according toclaim 1, wherein the resin composition is free of β-diketone.
 10. Theresin composition for molding according to claim 1, wherein the resincomposition for molding contains the thermal stabilizer in an amountwithin the range of 0.4 to 10 parts by weight based on 100 parts byweight of the chlorinated vinyl chloride-based resin.
 11. The resincomposition for molding according to claim 1, wherein the resincomposition for molding contains the polyalcohol and/or the partialester of a polyalcohol in a total amount within the range of 0.05 to 3parts by weight based on 100 parts by weight of the chlorinated vinylchloride-based resin.
 12. The resin composition for molding according toclaim 1, further comprising a stabilizing aid.
 13. The resin compositionfor molding according to claim 12, wherein the stabilizing aid comprisesat least one of sodium adipate and hydrotalcite.
 14. The resincomposition for molding according to claim 12, wherein the stabilizingaid comprises an organic acid salt.
 15. The resin composition formolding according to claim 12, wherein the stabilizing aid comprises ahigher fatty acid salt.
 16. A molded body molded from the resincomposition for molding according to claim 1.